The common cold, any of over 100 rhinoviruses, is an infection of the upper respiratory tract (URTI). Symptoms include sore throat, stuffy nose, watery eyes and aches. Children often contract a cough as well. As winter settles in, it's useful to review what we know about these viruses, which account for 40% of all breathing illnesses.

You don't get a cold by getting cold A 2002 review of literature on colds and their causes published in Medicine & Science in Sports & Exercise represents one of the latest attempts to debunk the popular myth that--despite the colder weather bringing cold and fluseason upon us--becoming chilled causes colds. Researchers have repeatedly found no causal link between cold exposure and onset of the virus, nor any correlation between cold exposure and increased risk of infection. Examination of the myth has occurred in one form or another over many years, including one 1968 experiment during which subjects wearing only underwear were soaked in water and then placed in a wind tunnel. They contracted colds at no greater a rate than the unexposed controls.

What research has supported over the years is that colds are most often picked up from a person's hands coming into contact with the nasal secretions of others with the virus. You get a cold by touching doorknobs, phones, subway straps and other shared surfaces, then touching your eyes, nose or any other port of entry. To a lesser extent, you may contract the virus by walking through air harboring someone's recent sneeze or cough particles. A cold is most contagious in the first few days after symptoms develop.

Treatment and prevention

A cure for the common cold remains elusive. The infection usually resolves itself in a week, but cold medications may help alleviate symptoms.

Analgesics offer relief from discomfort; expectorants may help expel the virus quicker. Decongestants can help open stuffed nasal passages; antihistamines may dry a runny nose. If you suffer from an unproductive, dry cough, a cough suppressant makes sense. You should try to target your (or your child's) specific set of symptoms. Be aware that antihistamines cause drowsiness, which can aid in the bed rest that your body needs to fight the virus, but poses a problem behind the wheel or at work. Decongestants should be avoided by people with hypertension or heart disease. Drinking fluids and inhaling steam may keep secretions loose and easier to expel.

Good hygiene, moderate exercise, and what may be termed social vigilance are your best defenses against colds. Frequently wash your hands, particularly if you are in touch with well-trafficked areas and surfaces. Stay away from colleagues and family members known to be infected, and avoid touching your face as much as possible.

There is mounting evidence that moderate exercise raises white blood cell count and can improve one's adaptive immune system. For example, higher levels of infection-fighting interferons were discovered in moderately trained cross country skiers in a 2001 study examined in the Jan/Feb Running & FitNews. The healthy controls who did not exercises did not experience the increase.

To determine if it's okay to run, perform the neck check. If your symptoms, are from the neck up--runny nose, watery eyes or a mild sore throat--give running a try. You might cut your mileage in half. But, a deep cough or general aches mean rest, and never run with a fever. Heart inflammation can occur, and this may be downright dangerous.

Echinacea and high doses of vitamin C have intermittently been shown to help prevent colds, but despite their popularity, conclusive evidence remains at large. In one double-blind study from May of last year, the vitamin C group consistently contracted fewer colds than the placebo group. But self reported cold symptoms have long been the bane of studies of URTI, and other research has shown vitamin C to be ineffective in preventing colds.

Regarding echinacea, one review of the literature states: "The majority of the available studies report positive results. However, there is not enough evidence to recommend a specific [e]chinacea product, or [e]chinacea preparations for the treatment or prevention of common colds."

Colds and children

Finally, be aware that a child's nasal and respiratory secretions contain higher concentrations of cold virus than do an adult's. This unfortunate fact, combined with an often lesser attention to hygiene than adults and much time spent in the close quarters of schools and day care centers, means children tend to not only contract more colds, but to transmit them easier to adults and other children. Teach your child to cover his or her mouth when coughing and to sneeze into a handkerchief, as well as to wash hands before meals and to keep a runny nose wiped.